Carburetor



May 20, 1930.

IE. SEIGNOL 1,759,666

CARBURETOR Filed June 25; 1927 {Sheets-Sheet vl Patented May 20, 19.30

EDOUARD sEIGNoL,

10F Panis, FRANCE 4 CARBURETOB.

' Application led June25, 1927, Serial No. 201,382, and in Franoe'June 2 6, 192,6.

The present invention relates to improve ments in self feeding carburetors for internal combustion engines. The object of these im provements is to provide a'carburetor for feeding an engine, especially a motor car, 'a motor boat or aeroplane engine, from'a fuel tank located at a relatively vgreat horizontal' distance from the engine and at a substantial- 1y lower level; Another object .of the invention is to dispense in such carburetois with the ordinary fuel exhauster or the like and with the constant level devices ordinarily used. A further object of the invention is to improve the efficiency andthe *working of the engine when slow running or yat normal speed especially when the throttle valve being nearly fully or fully open the engine is submitted to variations in speed according to the load. A still further object of the invention is to providefor the engine a large torque at slow speed and, as a consequence, to dispense with a frequent use of the change speed gear onV a motor car even when the engine 'is a small one comparatively to the weight ofl 2" the car. Again a still further object of the invention is to ensure an economy in fuel consumption and a correct Carburation for all speeds of the engine. l

The invention is illustrated by i\'ay of example intlie accompanying drawings.

ln these drawings: i Fig. 1 shoivs a diagrammatic side elevation at small scale, of a chassispiovided with a carburetor according to the present invention. r Fig. 2 shows a longitudinal section, at an enlarged scale, of the carburetor properly so called. Fig. 2 is a continuation of the; right hand end ot'Fig. 2,.showing the trap in the main fuel tank. l l

Fig. 3 shows a fragmentary crossl section through A-A of Fig. 2. l

Fig. 4 shows a longitudinal section through B--B of Fig. 2..

scale of a construction detail.

Fig. 6 shows a fragmentary cross sectionthrougli C-C of Fig. 2,-

Fig. 7 shows a fragmentary longitudinal Fig. 5 shows an elevation on a 'stillflargen section,` of a modification of the main mixing chamber shown iii Fig. 2. l

As shown in Figs. 1 to 6 the carburetor comprises two parts a and b connected together by a piping c. The part a is what may be called a primary carbureting device and produces a very i'ich carbureted mixture by mixing with air a great proportion of liquid fuel contained in a lower tank 1. rllie'part b is what may be called a secondary carbureting device and admixes with the very rich carbuieted4 mixture made by a the correct amount of air for feeding the engine 2 at any speed. The device a is located close to and above the fuel tank 1 at the rear of the chassis and at a relatively low level. The part I) is located close to the motor and above the level of the fuel in tank 1.

`The primary carbureting device a comprises a Venturi tube 3 with a'convergent part 4 and a divergent part 5. The restricted portion 6 of this venturi communicates through a condtiit 7 8 with a chamber 9 to which leads va pipe 10'secured, similarly to the venconnects the divergent part of the venturi 3 to the secondary carbureting device i vThis device b comprises an inlet pipe 13 y lea-ding from a'ventu'ri 14 with a convergent part 15 and `'divergent part 1G. InI the inlet pipe is positioned the usual-throttle valve 17 Y for regulating the flow of carbureted mixture to the engine. In the venturi 14 a little downstream from the throat 18 opens the pipe 12. Upstream to the Venturi 14` is the air inlet 19. The opening of this inlet is controlled by a rotative throttle valve -2() mounted on trunnions 21-22 turning in a casing 23. It will be noted that this valve is pneumatically balanced against movement in respouse to differences invair pressure on opposite sidesthereof, or variations in' flow of `air therethrough. The valve is provided with two openings 24-25 and two solid Aparts 249-25. The opening 25' is capable of regis tering progressively with the air inlet 19 when the valve 20 turns in the direction of 1 the arrow F, opening progressively this air inlet until it is wide open, the openings 24-25 being as large as the air inlet 19.

On the trunnion 22 of the valve 2O is secured an arm 26 which is connected by links 27 to the rod 28 ofl a piston 29 movable in a cylinder'30. This cylinder communicates through the conduit 31 with the interior of the carbureting device B at a point between the valves 17 and 2()r and preferably between the throttle 17 and the throat 18 and still more preferably at a point 32 in the divergent part 16 of Jthe venturi 14. A' spring 33 surrounding the trunnion 22 and iixed at one end to the casing 23- and at the other end to the arm 26 tends to force the piston 29 to the lower end of the cylinder 30 and consequently the valve 2O to close the air inlet 19, the solid part 25 coming .to register with said air inlet.

' lVhen the throttle Valve 17 is closed as shown yin F ig. 2 no depression exists in the venturi'14 and no suction is exerted on the opening of the tube'32 in Vsaid venturi; no vacuum is transmitted to the cylinder 30 and the spring 33 closes the air inlet valve 20.

When for normal runningthe throttle has been opened the engine sets up a depression in the inlet pipe 13 and venturi 14 up to the air throttle 20. This suction acts through` the tube 12 on the venturi 3. Air is sucked in said venturi and, as it passes through 'the throat G it sucks up liquid fuel through conduits 7 and 8, chamber 9 and tube 10 from the tank 1 making a very rich carbureted mixture which is conveyed through tube 12 to the venturi 14. The same suction acts also through the conduit 31on the inside of the cylinder 30 then on thepiston 29, which compresses the spring 33 and opens the air throttle 20.

l/Vhen at normal speed under such a load that it is forced to diminish speed although the throttle `17 is 'maintained open, the depression in the inlet 13 and venturi 14 is reduced; the carburetion is then influenced simultaneously in the device a and in the device I; and is not, for the moment, kept at its best mixture. The 'variation ot' suction however comes into action to regulate air admission und the depression being less than when the engine was revolving at 'full speed, the spring 33 will torce thepiston 29 down to a certain extent and partially close the airthrottlc 20. 'lhe quantity ot air admitted will consequently decrease and if vthe spring 33 is properly tensioned it will be pos sible to have the air decrease not only positively but also relatively to the amount oi rich mixture produced by the device a und admitted iu the device. b. v

The more the speed of the engine diminishes the less will be the depression in the venturi 14 and consequently the greater will be the extent to which the spring 33 will torce the piston 29 downward and close the throttle 2U. lhc regulation will consequently be continuous and by suitably determining the arca the engine comes' ci' the piston and the strength of the spring the best value for each speed ofrotation of the engine for the admission of rich mixture and of air to the device I) can be maintained. This regulating device not only maintains a correct regulation whatever may be the de` gree of opening of the throttle 17 but more? over it isy particularly effective when the throttle 17 is fully open and the engine is unl der a variable load.

The carburetor as illustrated'in Figs. 1 to 4 also comprises a slow running device which cooperates with the normal running .device already described. This slow running device comprises a Venturi tube 34 having a convergeut part and a divergent part 36 and a. throat 37 `which communicates with a tube 38 leading close'to the bottom of fuel tank 1. A pipe 39 connects lthe venturi 34 to a conduit 40 which opens in the inlet 13 downstream of the throttle valve 17. rlhe cross section of said conduit is regulated by a needle valve 42 provided with longitudinal transverse passages. 41 and 43 shown. The passage 43 maintains a constantly open connection between the pipe 39 and the inlet 13 whilst the passage 41 provides for constant communication between atmospheric air and the said inlet.

The suction exerted by the engine is trans- `mitted through the conduit 40 to the passages 4l. vand 43 and pipe 39 to venturi 34. .Air is admitted in this venturi which sucks rup liquid fuel from the tank 1, which fuel is adinixed with the air entering the venturi and forms a veryrich mixture which is conveyed to the inlet 13 through pipe 39.

'lhere the rich mixture receives an addition of 'fresh air by the passage 41 in order to produce the slow running carbureted mixture.

1When the engine is running 'slowly and not under load the throttle 17 is closed and it is fed only through pipe 39 by venturi 34. lhen running normally the throttle 17 is wide open and the engine is fed only through pipe 12 by venturi 3 as the passage is a. very small one. very small in venturi 14 and the speed of air in venturi 34 is consequently too small to litt :Enel from the tank 1. it may occurv that ltor a certain position of the throttle 17 and for a certain speed of the engine the latter will be fed by both slow and normalrunningT devices, the working eiiect ot the `throttle valve 20 acting on both said devices.

llt should be stated that the valve 20 and .its actuating device also serve to ensure a ,quick acceleration oi' the engine from slow to normal running when as aforesaid the conduit 31 is provided with a regulating needle valve 31?. movement oi the piston 29 and thus to prevent the valve 2O from beingopenedtooquick! ly when the throttle valve 17 is suddenly ac-V ',lhis valve 31L acts to brake the,

The depression is at that time tuated for accelerating the engine to full speed. If the valve 20 be too quickly opened again set in action and the column of air or carbureted mixture in tube 12 is set in motion. By braking the opening of the valve 20 when the throttle 17 is suddenly opened the suction transmitted to the venturi 14 rst actson the tube 12 and the ven- 'turi 3 and, at the same time, on the conduit 31 but as the vacuum acts slowly on the piston 29 the' air valve 20 alsoopens slowly and air is admitted through 19 at the right time and in correct progressive proportions relatively to the rich mixture enteringthe lventuri'through 12.

The acceleration is, also facilitated by the liquid fuel accumulated in the recess surrounding the throatv of the venturi 3. When the sucking action of the venturi 3 ceases the fuel filling the chamber 9 vpartly flows .in

the recess above referred to and remains.

will ensure progressive opening or closing of the air passageduring openingand closing movement of the air inlet valve.

In the' modification shown in Fig. 7 the piston 29 instead of being actuated on one side by suction and on the other by a spring, is on the upper side actuated by depression in the downstream of the throttle 17 through' in the figure, which allows even then a slow admission of4 air. When the throttle 17 is open the depression at 31b belng greater than that at 31 draws the piston down and opens the throttle 20. The throttle 17 being nearly or fully open, if the epgine attempts to vary in speed, the depression in the carburetor changes, the difference between the depressions at 31 and 31b will vary similarl and the piston Willfbe displaced by the new iffrence until the piston having operated the air inlet apparatus the suction in the carburetor rey gainsits normal value thus reestablishing the equilibrium of the air regulating system.

ligs. 2 and 6 is illustrated a devicke for obtaining a greater regularity in the production of the very rich carbureted mixture byl means of the device a. The fuel tank isclosed and air tight and a tube 44 is' provided which leads from the bottom ofthe tank and` opens in the atmosphere. A passagel 45 connects the upper part of the tank l to the throat 37 of venturi 34. For any speed of the engine a y depression is created in the tank by the engine through the conduit 40, the tube 39,*the

' venturi 34 and the passage 45, air being sucked ,liquid fuel as regards the venturis 3 and 34 is always the same whatever may be the level of the fuel in the tank 1 and the venturis work exactly under the same conditions asif the level of the fuel in the tank was constant.

In order to prevent entrance of air into the tank and at the same time' prevent any excess of pressure in the tank by heat or other reasons which could cause the fuel to be expelled through the tube 44, the tank is provided with a check valve 46 having a seat 47.

The present invention can be considered as a modification or improvement of that described in my U. Sjapplication Serial No. 90,- 958 of February 26, 1926 in that in the present invention the suction on the piston regulating the auxiliary valve is not produced by the depression on the downstream side of the thrcttle, but in the upstream side, with a spring or similar element tending to close the valve opposed to the suction in order to open the air inlet shutter other than by the effect of the current of air entering the carburetor under direct iniuence of the engine suction. From this it results that the regulation which beforeV was relatively rapidand only applied during the period of-passing from slow to normal running, is now produced at all times- The invention can moreover for the samey reasons be considered as -an improvement of thdcarburetor described in my U. S. A.' application Serial No. 91,586 of March 1, 1926.

It is seen that a carburetor constructed according to the present invention produces great flexibility of control of the engine, allowing it to descend to an extremely lo1 speed of rotation withea high degree of torque. This is due to the fact that the regulation of air supply in the carburetor (primary and ysecondary carburetor) is such as to prevent the carbureted mixture from becoming too poor as regards fuel when at slow speed the throttleV Y valve is widely opened. yThus, the engine .cannotl choke owing to much air entering the carburetor. Y

What is claimed is: 1. In a self-feeding `carburetor the combination of an internal combustion engine intake, a main liquid fuel tank located at a lower level than the said intake, a primary venturi positioned above the level of the fuel' in the main tank and close to said tank, aconduit connecting the throat of the venturi dip rectlyto a point slightly above the bottomlof the tank, a secondary venturi in the intake, a throttle valve downstream the secondary Venturi regulating the flow of carbureted mixture to the engine, a piping connecting the primary venturi to a point slightly downstream of the throat of the secondary venturi Jtherein, a pneumatically balanced air throttle valve regulating the flow of air in the secondary Venturi and influencing theow .of air in the primary venturi, a piston movable in a cylinder, a cylinder exhaust conduit connecting one face of the said piston with a point located between the two throttle valves, a 2o spring tending to close the air regulating throttle valve and a connection between the said piston and the said air regulating throttle valve, the movements of the pistonunder the iniuence of the depression above referred to and of the said spring causing the air regulating throttle valve to be moved towards its closure position when the depression diminishes and vice versa and means for regulating the section of the said cylinder exhaust coni l3o duit.

2. In a self-feeding carburetor the combination'of an internal combustion engine intake, a--main liquid fuel tank located at a lower level than the said intake, a primary venturi positioned above the level of the fnel in the main tank and close to said tank, a conduit vconnecting-the throat of the venturi `to a point slightly above the bottom of the tank, a secondary venturi in the intake, a

` 40 throttle valve downstream, the said secondary venturi regulating the iow of cai-buietcd mixture tothe engine, a piping connecting the primary venturi to a point within the secondary venturi slightly downstream the throat o f the secondary venturi, an air throttle valve regulating the fiow of air in the secondary venturi and influencing the flow ol" air in the primary venturi, a second primary venturi located as the first primary one and connected to the bottom of the tank, a second piping connecting the'said second primary venturi to the intake of the engine at a point positioned downstream of the regulating throttle valve therein, means for 5 admixing air to the carbu'reted `mixture delivered by the second primary venturi, a piston movable in a cylinder, a conduit connecting one face of the saidpiston with a point located between the two throttle Valves,

a spring tending to close the air [regulating throttle valve and a connection between the said piston and the said air regulating throttle valve the movements of thenpiston under the influence of the depression between the two throttle valves and of the said spring,

causing the air regulating throttle valve to be moved toward its closure position when the depression diminishes and vice versa.

3. ln a self-feeding carburetor for internal combustion engines, the combination of an air tight main liquidlfuel tank located at a -lower level than the engine intake, a primary venturi positioned above the level of the fuel in the main tank and close to said tank, a conduit connecting the throat of the venturi to a point slightly above the bottom of the tank, a secondary venturi in the intake, a throttle valve downstreamthe said secondary venturi regulating the` flow of carbureted mixture to the engine, a` piping connecting the primary venturi to a point slightly downstream the throat of the secondary venturi therein, an air throttle valve regulating the flow of air in the sec-` ondary Venturi and influencing the flow of air in the primary venturi, a second primary venturi located as the first primary one and connected to the bottom of the tank, a piping connecting the said second primary venturi to the intake of the engine at a point positioned downstream of the regulating throttle valvetherein, means for admixing air to the carbureted mixturei delivered by the second primary venturi, a passage connecting the throat of the said second primary venturi to the inside of the said fuel tank above the level of the fuel therein, and a tube opening at one end to the atmosphere and at the other end close to the bottoni of the tanka 4. ln a self-feeding carburetor the combi nation of an internal combustion engine intake, an air tight liquid fuel tank located at a lower level than the said intake, 'a primary venturi positioned above the level of the fuel in the tank and close to said tank, a conduit connecting the throat of the venturi to a point slightly above the bottom of the tank, a secondary venturi in theintake, a throttle valve downstream of the said secondary venturi regulating the tiow of carburcted mixture to the engine, a piping conl necting the primary venturi to a point slightl ly downstream of the throat of the secondary venturi, an air throttle valve regulating the flow of air in the secondary venturi and influencing the flow of air in the primary venturi, a second primary venturi located as the i first primary one and connected to'the botT tom of the tank, 'a second piping connecting 120 the said second primary venturi to the inl take of the engine at a point positioned downstream of they regulating throttle valve therein, means for admixing airito they car- `Ibureted'mixture delivered by the second pri- 125'.

mary venturi, a passage connecting the throat ofthe said second primary venturi to the inside of the said fuel tank above theY level of the fuel therein, a tubey opening at one end to the atmosphere and at the other no end close to the bottom of the tank, a piston movable in a, cylinder, a conduit connecting one face of the said piston with a point 1ocated -loetvveen the two throttle valves, a spring tending to close the air regulating throttle valve, and a connection between the said piston and the said, air regulating l throttle valve, the movements of the piston under the influenceof the depression above referred to and of the said spring causing the air regulating throttle valve to be moved towards its closure position when the depression diminishes and vice versa. In testimony whereof I have aixed my signature.' 15 EDOUARD sEIGfNoL. 

